High-speed camera objective



I StAHUH HUUP OR 3,350,157 H OQT Get. 31, 1967 SQLISCH T I 3,350,157

' HIGH-SPEED CAMERA OBJECTIVE Filed March 30, 1964 d3 d4 45 45 47 as" 49am an 8 r9 r10 lrll rlZ RUDOLF SQLISCH' WA LTER WOLTCHE Jn ven/ors.

, AGENT United States Patent ABSTRACT OF THE DISCLOSURE High-speedcamera objective with a front and a rear component of three lens memberseach, defining a diaphragm spaced between them, the first two members ofv the rear component being doublets with forwardly convex cementedsurfaces of, respectively, negative and positive refractivity.

Our present invention relates to a high-speed objective for photographicor cinematographic cameras, more particularly an objective whoseback-focal length equals or exceeds half its overall focal length.

Known camera'objectives of this type, designed for the extremely highaperture ratio of about 1:1, suffer from a markedly decreased luminosityat the corners of the image field. It is, therefore, an object of ourinvention to provide an objective of this type, having the largeaperture ratio referred to, whose luminosity at the corners is relatedto that at the center by a ratio equaling or preferably exceeding 1:2. I

A related object of our invention is to provide an objective of thisdescription of high resolving power adapted to be used for specificpurposes, such as television, requiring high-contrast reproduction. v

The foregoing objects are realized, in conformity with this invention,by the provision of an objective composed of six lens members of whichthe first, second, fifth and sixth (counting from front to rear, i.e.from the object side to the image side of the system) are positivelyrefracting whereas the third and fourth members are negativelyrefracting and are constituted by a pair of menisci facing each otherwith their concave sides across a relatively large air space, generallyutilized as a diaphragm space; the fourth lens member, i.e. the morerearwardly positioned one of the two negative menisci, and the positivefifth member immediately following that meniscus are doublets, eachcomposed of two lenses of opposite refractivity, the collective lensforming part of the fourth member having an axial thickness which is atleast equal to and preferably in excess of 12% of the overall focallength of the objective.

According to a more specific feature, the collective lenses of the twodoublets are biconvex and are disposed rearwardly of the associatedcollective lenses, the cemented surface separating the two lenses ofeach doublet being negatively refracting in the case of the fourthmember and positively refiracting in the case of the fifth member.

According to a further feature of the invention, the positive sixthmember (whose rear surface facing the image side may be convex, plane orconcave) has a convex front surface whose radius of curvature has an 65focal length of 60.58.

' cemented fifth member and the sixth absolute value at most equal toand preferably less than one third that of the radius of curvature ofthe advantageously concave front surface of member.

We have found that an objective of this construction can be designedwith an aperture ratio as high as 1:0.95 and with a luminosity ratioalong the image diagonal of the positive fifth about 121.3, the bundleof slanting incident rays at maximum image angle being thus unusuallylarge; at the same time the maximum spherical zonal aberration was foundto amount to less than 0.2% of the overall focal length upon a zerocorrection of the marginal ray.

We further determined that the desired large back-focal length, whichmay be in excess of 60% of the overall focal length, can be realized ifthe axial thicknesses and separations of all the lens members are soselected that the total length of the assembly, While exceeding theoverall focal length, is not greater than substantially 1.8 times thatfocal length. At the same time, the axial length of the front component,which consists of the first three members, should be less than the axiallength of the rear component, constituted by the last three members, theintervening air space extending axially over at least 25% of the overallfocal length.

For the purpose of expanding the astigm-atic image shells andlengthening the lower coma rays, we have discovered that the refractiveindices of the glasses of the negative third member, the collectivecomponent of the member should be greater than 1.62.

A typical embodiment of our invention is shown in the sole figure of theaccompanying drawing.

The objective shown in the figure consists of a front component F and arear component R. Component F is constituted by a front member I in theform of a positive meniscus L a second member II represented by asimilarly shaped lens L and a third member III in the form of a meniscusL with a rearwardly facing concave side. The lenses L -L all singlets,have radii of curvature r to r,; and axial thicknesses d d and d theirseparations from one another being designated d; and d A large air spaced accommodating a diaphragm D, separates component F from component Rwhose first member IV is a negative doublet composed of a biconcavedispersive lens L (radii r r and thickness d and a biconvex collectivelens L (radii r r and thickness d,,). As the refractive index of lens Lexceeds that of lens L the forwardly convex cemented surface r, isnegatively refracting. Member IV is separated by a small air space d,from a meniscus-shaped positive doublet V also composed of a biconcavedispersive lens L (radii r r and thickness d and a biconvex collectivelens L (radii r r and thickness d the forwardly convex cemented surfacer is positively refracting as the refractive index of lens L exceedsthat of lens L The rear member VI,

this system has a relative aperture of 1:095 and a back- I ThicknessesLens Radli and 11 w Separations n =+146.36 I L d1 12.18 1.6200 60.3

d; 0.41 Air space r; =+10fi 73 F II 14----.- d: 12.18 1.6200 60.3

d4 0.41 Air space rs 62 10 I L;. d5 21.11 1.7410 28.1

41 54 d, 35.53 Air Space (Diaphn) 134------ d1 5.08 1. 7410 28. 1 IV rs=+203 I Ls-----. (is 28.42 1.7200 50.3

d 0.41 Air space m=915 62 LL"--- dm= 4.11 1.5960 39.2 R V T11=+132.13

L1---- dn= 18.27 1.6910 54.8

du= 0.41 A1! space T13=+116.00 VI L d1a= 12.18 1.6910 54.8

dmul=15010 The thickness d of biconvex lens L equaling 18.27 in theforegoing table, will be seen to exceed 12% of the overall focal length.The front radius r of member VI, equaling +116, has an absolute valueless than A that of front radius r of member V, which is given as915.62. The total axial length of the front component F, measured fromthe left-hand vertex of lens L to the right-hand vertex of lens Lamounts to 46.29 and is thus less than the total axial length of therear component R, measured from the left-hand vertex of lens L to theright-hand vertex of lens L which amounts to 68.88; the interveningspace d measuring 28.42 units, exceeds of the overall focal length.Finally, the axial length d of the entire assembly, of numerical value150.7, lies between 1 and 1.8 times the focal length. 1

Although only the lens members IV and V have been shown as doublets, inconformity with a major feature of our invention, it will be apparentthat some or all of the remaining members could also be provided withcemented surfaces for purposes of further correction of residualaberrations.

We claim: 1

A high-speed camera objective composed of six len members following oneanother and comprising, in order from the object side to the image sideof the objective, a positive first member consisting of a first lens L apositive second member consisting of a second lens L a negative thirdmember consisting of a third lens 1 a negative fourth member composed ofa fourth and a fifth lens L L a positive fifth member composed of asixth and a seventh lens L L and a positive sixthmember consisting of aneighth lens L said lenses having radii of curvature r to r andthicknesses and separations d to ai whose numerical values, based upon anumerical value of 100 for said overall focal length, together withstantially as given in the following table:

Thicknesses Lens Radii an m u Separations d: 0.41 Air space 1'; =+106 73II--- 1 d; 12.18 1. 6200 I 60.3

T4 =+263A8 d 0 41 Al r s ace 4o r. 62.10 4 p 111.--- 113.... ii; 21.111.7410 I 28.1

' d" 3553 I Al D1 h S n 4154 o I r paee( ap r) L4- d1 5.08 1. 7410 28. 1IV. r =+203.10 13s--.- d; 28.42 1.7200 50.3

d 0.41 Air space T1o=-9l5 62 Lsli o 4.11 1. 5960 39. 2 v-.-" Tu=+132.13

L1. d1i= 18.27 1. 6910 54. 8 m=--132.13

dn= 0.41 Air space Tra=+116.00 VI..-. Ls-.--{ d1a= 12.18 1. 6910 54.8

dwtsl= 150.70

References Cited I v UNITED STATES PATENTS 2,828,671 4/1958 Murakami350-215 2,979,988 4/1961 Aklin 350-217 JEWELL H. PEDERSEN, PrimaryExaminer. R. I. STERN, Assistant Examiner.

